这很可能在Tomcat中造成内存泄漏？

我configuration了tomcat以使用不同的外部开源。

但是，在tomcat运行了几分钟后，我得到：

SEVERE：Web应用程序[/ MyProject]创build了一个types为[java.lang.ThreadLocal]（值为[java.lang.ThreadLocal@1b3f02f]）的键和一个types为[org.apache.axis.MessageContext]的ThreadLocal（值[org.apache.axis.MessageContext@5dbd4e]），但在Web应用程序停止时未能删除它。 这很可能造成内存泄漏。

什么可能导致它？

我要去哪里看？ 它可以在Tomcat上数据池吗？

这是什么意思在Tomcat线程？

EDITED

这是我的全部痕迹。 应用程序似乎重新加载它的上下文，而它仍然在运行 – 我不知道为什么！

Mar 13, 2011 10:56:12 PM org.apache.catalina.core.StandardContext reload INFO: Reloading this Context has started Mar 13, 2011 10:56:12 PM org.apache.catalina.core.StandardWrapper unload INFO: Waiting for 1 instance(s) to be deallocated Mar 13, 2011 10:56:13 PM org.apache.catalina.core.StandardWrapper unload INFO: Waiting for 1 instance(s) to be deallocated Mar 13, 2011 10:56:14 PM org.apache.catalina.core.StandardWrapper unload INFO: Waiting for 1 instance(s) to be deallocated Mar 13, 2011 10:56:14 PM org.apache.catalina.core.ApplicationContext log INFO: Closing Spring root WebApplicationContext Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc SEVERE: The web application [/MyProject] registered the JBDC driver [com.mysql.jdbc.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc SEVERE: The web application [/MyProject] registered the JBDC driver [oracle.jdbc.driver.OracleDriver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/MyProject] appears to have started a thread named [NioSocketAcceptor-1] but has failed to stop it. This is very likely to create a memory leak. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/MyProject] appears to have started a thread named [NioProcessor-1] but has failed to stop it. This is very likely to create a memory leak. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/MyProject] appears to have started a thread named [NioProcessor-4] but has failed to stop it. This is very likely to create a memory leak. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/MyProject] appears to have started a thread named [bitronix-disk-force-batcher] but has failed to stop it. This is very likely to create a memory leak. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/MyProject] appears to have started a thread named [bitronix-scheduler] but has failed to stop it. This is very likely to create a memory leak. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/MyProject] is still processing a request that has yet to finish. This is very likely to create a memory leak. You can control the time allowed for requests to finish by using the unloadDelay attribute of the standard Context implementation. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/MyProject] appears to have started a thread named [NioProcessor-7] but has failed to stop it. This is very likely to create a memory leak. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/MyProject] appears to have started a thread named [NioProcessor-2] but has failed to stop it. This is very likely to create a memory leak. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [/MyProject] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@1b5a8e1]) and a value of type [org.mvel2.debug.DebuggerContext] (value [org.mvel2.debug.DebuggerContext@16259fd]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [/MyProject] created a ThreadLocal with key of type [org.apache.axis.utils.XMLUtils.ThreadLocalDocumentBuilder] (value [org.apache.axis.utils.XMLUtils$ThreadLocalDocumentBuilder@84b0b4]) and a value of type [com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl] (value [com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl@16d2cfa]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [/MyProject] created a ThreadLocal with key of type [null] (value [com.sun.faces.util.Util$1@16bbac9]) and a value of type [java.util.HashMap] (value [{com.sun.faces.patternCache={ = }}]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [/MyProject] created a ThreadLocal with key of type [java.lang.ThreadLocal] (value [java.lang.ThreadLocal@1b3f02f]) and a value of type [org.apache.axis.MessageContext] (value [org.apache.axis.MessageContext@5dbd4e]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [/MyProject] created a ThreadLocal with key of type [org.apache.axis.utils.XMLUtils.ThreadLocalDocumentBuilder] (value [org.apache.axis.utils.XMLUtils$ThreadLocalDocumentBuilder@84b0b4]) and a value of type [com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl] (value [com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl@378584]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [/MyProject] created a ThreadLocal with key of type [org.springframework.core.NamedThreadLocal] (value [Transactional resources]) and a value of type [java.util.HashMap] (value [{org.hibernate.impl.SessionFactoryImpl@ccc27b=org.springframework.orm.hibernate3.SessionHolder@4f6ada}]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. Mar 13, 2011 10:56:15 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap SEVERE: The web application [/MyProject] created a ThreadLocal with key of type [null] (value [com.sun.faces.application.ApplicationAssociate$1@1f01fcf]) and a value of type [com.sun.faces.application.ApplicationAssociate] (value [com.sun.faces.application.ApplicationAssociate@1b85528]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak. 2011-03-13 22:57:27,734 ERROR ( ContextLoader.java:220) - Context initialization failed org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'transactionManager' defined in class path resource [applicationContext-hibernate.xml]: Cannot resolve reference to bean 'sessionFactory' while setting bean property 'sessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [applicationContext-hibernate.xml]: Invocation of init method failed; nested exception is java.lang.OutOfMemoryError: Java heap space at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:328) at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:106) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1325) 

Answer 1

这个消息实际上很清楚：有些东西创build了一个types为org.apache.axis.MessageContext的ThreadLocal – 这是一个很好的提示。 这很可能意味着Apache Axis框架本身忘记/无法清理。 在Logback中发生同样的问题 。 您不应该打扰太多，但向Axis团队报告错误可能是一个好主意。

Tomcat报告此错误，因为ThreadLocal是根据HTTP工作线程创build的。 你的应用程序被取消部署，但是仍然存在HTTP线程 – 以及这些ThreadLocal 。 这可能会导致内存泄漏（ org.apache.axis.MessageContext不能被卸载）以及将来这些线程被重用时的一些问题。

有关详细信息，请参阅： http : //wiki.apache.org/tomcat/MemoryLeakProtection

Answer 2

我在我的CDI @ApplicationScoped bean中添加了以下内容到@PreDestroy方法中，当我closuresTomEE 1.6.0（tomcat7.0.39，截至今天）时，它清除了线程本地。

 /* * To change this template, choose Tools | Templates * and open the template in the editor. */ package pf; import java.lang.ref.WeakReference; import java.lang.reflect.Array; import java.lang.reflect.Field; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * * @author Administrator * * google-gson issue # 402: Memory Leak in web application; comment # 25 * https://code.google.com/p/google-gson/issues/detail?id=402 */ public class ThreadLocalImmolater { final Logger logger = LoggerFactory.getLogger(ThreadLocalImmolater.class); Boolean debug; public ThreadLocalImmolater() { debug = true; } public Integer immolate() { int count = 0; try { final Field threadLocalsField = Thread.class.getDeclaredField("threadLocals"); threadLocalsField.setAccessible(true); final Field inheritableThreadLocalsField = Thread.class.getDeclaredField("inheritableThreadLocals"); inheritableThreadLocalsField.setAccessible(true); for (final Thread thread : Thread.getAllStackTraces().keySet()) { count += clear(threadLocalsField.get(thread)); count += clear(inheritableThreadLocalsField.get(thread)); } logger.info("immolated " + count + " values in ThreadLocals"); } catch (Exception e) { throw new Error("ThreadLocalImmolater.immolate()", e); } return count; } private int clear(final Object threadLocalMap) throws Exception { if (threadLocalMap == null) return 0; int count = 0; final Field tableField = threadLocalMap.getClass().getDeclaredField("table"); tableField.setAccessible(true); final Object table = tableField.get(threadLocalMap); for (int i = 0, length = Array.getLength(table); i < length; ++i) { final Object entry = Array.get(table, i); if (entry != null) { final Object threadLocal = ((WeakReference)entry).get(); if (threadLocal != null) { log(i, threadLocal); Array.set(table, i, null); ++count; } } } return count; } private void log(int i, final Object threadLocal) { if (!debug) { return; } if (threadLocal.getClass() != null && threadLocal.getClass().getEnclosingClass() != null && threadLocal.getClass().getEnclosingClass().getName() != null) { logger.info("threadLocalMap(" + i + "): " + threadLocal.getClass().getEnclosingClass().getName()); } else if (threadLocal.getClass() != null && threadLocal.getClass().getName() != null) { logger.info("threadLocalMap(" + i + "): " + threadLocal.getClass().getName()); } else { logger.info("threadLocalMap(" + i + "): cannot identify threadlocal class name"); } } } 

Answer 3

关键的“事务性资源”看起来像是在没有正确的事务的情况下与数据库交谈。 确保事务pipe理configuration正确，并且不存在不在@Transactional注释下运行的DAO调用path。 当您在控制器级别configuration事务pipe理但是在计时器中调用DAO或正在使用@PostConstruct注释时，很容易发生这种情况。 我把它写在这里http://georgovassilis.blogspot.nl/2014/01/tomcat-spring-and-memory-leaks-when.html

编辑：它看起来像（也？）与弹簧数据-JPA已被固定在v1.4.3的一个错误。 我在LockModeRepositoryPostProcessor的spring-data-jpa源代码中查找了它，它设置了“Transactional Resources”键。 在1.4.3中它也会清除密钥。

Answer 4

有时这与configuration更改有关。 当我们从Tomncat 6.0.14升级到6.0.26时，我们看到了类似的东西。 这里是解决schemehttp://www.skill-guru.com/blog/2010/08/22/tomcat-6-0-26-shutdown-reports-a-web-application-created-a-threadlocal-threadlocal-过气，强行移除的/

Answer 5

当我们使用任何第三方解决scheme，而不使用清理活动的处理程序时，会出现此问题。 对于我来说这是EhCache发生的事情。 我们在我们的项目中使用EhCache进行caching。 我们经常在日志中看到以下错误

  SEVERE: The web application [/products] appears to have started a thread named [products_default_cache_configuration] but has failed to stop it. This is very likely to create a memory leak. Aug 07, 2017 11:08:36 AM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/products] appears to have started a thread named [Statistics Thread-products_default_cache_configuration-1] but has failed to stop it. This is very likely to create a memory leak. 

而且我们经常注意到tomcat在开发过程中出现OutOfMemory错误失败，我们曾经做过后端更改，并多次部署应用程序以反映我们的更改。

这是我们所做的修复

 <listener> <listener-class> net.sf.ehcache.constructs.web.ShutdownListener </listener-class> </listener> 

所以点我试图做的是检查您正在使用的第三方库的文档。 他们应该提供一些机制来清理closures期间的线程。 你需要在你的应用程序中使用它。 除非不是由他们提供，否则不需要重新发明轮子。 最坏的情况是提供你自己的实现。

EHCache关机参考http://www.ehcache.org/documentation/2.8/operations/shutdown.html